IMPACTS OF INDUSTRIAL WASTES ON THE AGRICULTURAL SOIL IN WEST AREA OF ALGERIA: FRACTIONATION AND CONTAMINATION OF HEAVY METALS IN SOILS BY SEQUENTIAL EXTRACTION PROCEDURE

Abstract

The selected region is west of Algeria Ghazaouet exactly near industrial discharges from the production unit ALZINC which is the main productive zinc, sulfuric acid and copper in Algeria. Releases of the latter are stored in the form of dikes and pose a serious threat to the environment. Agricultural soil around these discharges are characterized by an alkaline pH, resulting mainly high carbonate levels, the average values in the cationic exchange capacity and a texture sandy soil. Geochemical points of view, these soils have high levels of Zn, Cd, Ni, Cr related to industrial discharges. Whereas Fe, Mn, Pb and Cu concentrations recorded in different places does not exceed the maximum tolerated levels in soils. Fractionation of these eight metals studied (Zn, Fe, Mn, Pb, Cu, Cr, Ni and Cd) shows that the fractions of the most important metal parts are stored in the remaining phase (Fe, Cr, Pb). The other metals (Zn, Mn, Cu, Cr, Ni and Cd) are mainly concentrated in the labile fraction (or mobilizable) which is represented by fractions: the exchangeable phase, the organic phase, and the carbonate phase phase oxides of iron and manganese which could subsequently contaminate food crops in these regions.